The invention relates to a replenisher supply device for photosensitive planographic printing plate processing apparatus (hereinafter referred to as "PS plate processing apparatus") which adds replenishers to the processing apparatus for processing a photosensitive planographic printing plate (hereinafter referred to as "PS plate") on which an image has been exposed.
Generally, a PS plate on which an image has been exposed is fed into a developing tank, where the surface of the plate receives a developing solution by means of spraying or the like and is developed while being rubbed by a brush, sponge, or the like. The light-sensitive layer of the non-image area of the exposed PS plate is swollen by applying developing solution containing an organic solvent and an alkaline aqueous solution. The swollen layer of the non-image area is then removed with ease by rubbing means such as a brush or sponge, leaving only the image area on the PS plate. This means that the developing solution contains, at this point of process, eluted substances such as a photosensitive substance. Further, since the developing solution is applied to the PS plate usually by means of showering when the plate passes through the developing tank, the solution is subjected not only to deterioration due to its being in contact with air, such as reduction in pH of the developing solution by dissolution of carbon dioxide gas, but also concentration due to evaporation of water from the processing solutions including the developing solution and a gum arabic solution. Once the developing solution loses its developing capability by processing a large volume of PS plates and/or the elapse of time and has finally reached its life limit, it must be replaced with a new developing solution. If the PS plates are processed beyond the limit of the developing solution, the photosensitive layer of the non-image area of PS plate remains, which may result in pint stains or instability in printing quality such as tone reproduction. To compensate for deterioration of the processing solutions caused by the processing of PS plates, the influence of carbon dioxide gas in the air, concentration of the processing solutions caused by evaporation of water, a replenisher for the developing solution, a replenisher for the gum arabic solution, and diluting water, and the like are supplied to the corresponding processing tanks.
However, in the conventional PS plate processing apparatus, each apparatus has a single replenisher supply device in the processing apparatus. As a result, when a plurality of PS plate processing apparatus are installed, a replenisher for each apparatus must be prepared and the labor for preparation operation is extremely cumbersome.
This invention has been made to overcome the above circumstances. Accordingly, an object of the invention is to provide a replenisher supply device for PS plate processing apparatus capable of simplifying preparatory and supplying work of replenishers.